A device and method for absorbing sulfur dioxide from boiler flue gas using iodine

Abstract

The invention discloses a device and method for absorbing sulfur dioxide from boiler flue gas by using iodine. The device comprises a flue gas inlet, an absorption tower, a packing layer and a demisting layer. The outlet of the flue gas inlet is connected to the inlet of the absorption tower. The packing layer and the demisting layer are sequentially installed in the upper part of the absorption tower from bottom to top. The absorption tower can detect sulfur dioxide. The packing layer and the demisting layer can resist the corrosion of sulfuric acid and hydroiodic acid. In the method, the flue gas inlet introduces sulfur dioxide-containing flue gas into the absorption tower, and the flue gas passes through the packing layer and the demisting layer in sequence and is discharged. The invention solves the problems existing in the current production of hydrogen from sulfur dioxide in sulfur-absorbing boiler flue gas.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of boiler flue gas and hydrogen preparation, and specifically relates to a device and method for absorbing sulfur dioxide in boiler flue gas by utilizing iodine. Background Art

[0002] Iodine is used to absorb sulfur dioxide in flue gas to obtain hydrogen iodide, which is used to produce hydrogen. This achieves waste utilization, environmental protection and the preparation of green hydrogen, and has good social and economic benefits.

[0003] The absorption tower is generally used to absorb sulfur dioxide in flue gas using iodine, but this method currently has the following problems:

[0004] (1) Iodine reacts with water and sulfur dioxide to generate sulfuric acid and hydroiodic acid. To separate sulfuric acid and hydroiodic acid, an excess of iodine needs to be added. Only when the solution density reaches 2.5 kg / L or more can sulfuric acid and hydroiodic acid be separated. A large amount of iodine is consumed in this process. The diameter of the absorption tower is generally large. To maintain the normal operation of the slurry circulation pump, a certain liquid level must be maintained, which consumes more iodine:

[0005] (2) Iodine is a relatively volatile substance. The escape of iodine vapor will cause pollution. At the same time, iodine is of high value. The escape of iodine vapor will increase the cost of hydrogen production.

[0006] (3) It is not possible to complete absorption and static separation in the same absorption tower. Summary of the invention

[0007] Aiming at the existing problems of producing hydrogen by absorbing sulfur dioxide from boiler flue gas, the present invention provides a device and method for absorbing sulfur dioxide from boiler flue gas by utilizing iodine.

[0008] The present invention is achieved by adopting the following technical solutions:

[0009] The present invention provides a device for absorbing sulfur dioxide in boiler flue gas by using iodine, comprising a flue gas inlet, an absorption tower, a packing layer and a demisting layer;

[0010] The outlet of the flue gas inlet is connected to the inlet of the absorption tower. The packing layer and the demisting layer are installed in the upper part of the absorption tower from bottom to top. The absorption tower can detect sulfur dioxide. The packing layer and the demisting layer can resist the corrosion of sulfuric acid and hydroiodic acid.

[0011] A further improvement of the present invention is that a flue gas booster fan is installed in the flue gas inlet, and the booster fan is used to increase the flue gas pressure to overcome the resistance of the packing layer and the demisting layer.

[0012] A further improvement of the present invention is that it also includes a water adding device and a smoke exhaust device, the water adding device is connected to the upper part of the demisting layer through an atomizing nozzle, the smoke exhaust device is installed on the top of the absorption tower, and the smoke exhaust device can detect sulfur dioxide and iodine content.

[0013] A further improvement of the present invention is that it also includes a slurry collecting tank, an iodine absorbing layer, a slurry circulating pump and an iodine adding device, the top of the slurry collecting tank is connected to the bottom of the absorption tower, the iodine absorbing layer is a fine-pore mesh, installed on the upper part of the slurry collecting tank, and granular iodine is placed thereon, the outlet of the iodine adding device is connected to the inlet of the iodine absorbing layer to provide granular iodine for the iodine absorbing layer, the inlet of the slurry circulating pump is connected to the first outlet of the slurry collecting tank, and the outlet of the slurry circulating pump is connected between the packing layer and the demisting layer through an atomizing nozzle.

[0014] A further improvement of the present invention is that the first outlet of the slurry collection tank is arranged at the lower part thereof and close to the bottom.

[0015] A further improvement of the present invention is that the diameter of the slurry collection tank is smaller than that of the absorption tower, and the slurry that can be stored inside the tank matches the flow rate of the slurry circulation pump, which can meet the normal operation of the slurry circulation pump.

[0016] A further improvement of the present invention is that one absorption tower is equipped with a plurality of slurry collecting tanks, and the absorption and static stratification of sulfur dioxide can be carried out continuously by switching the slurry collecting tanks.

[0017] A further improvement of the present invention is that it also includes a hydrogen iodide solution collecting tank, a mixed liquid collecting tank and a sulfuric acid collecting tank. The second outlet of the slurry collecting tank is at its bottom and is divided into three branches, the first branch is connected to the inlet of the hydrogen iodide solution collecting tank, the second branch is connected to the inlet of the mixed liquid collecting tank, and the third branch is connected to the inlet of the sulfuric acid collecting tank.

[0018] The present invention also provides a method for absorbing sulfur dioxide from boiler flue gas by using iodine. The method is based on the device for absorbing sulfur dioxide from boiler flue gas by using iodine, and comprises:

[0019] adding granular iodine to the iodine absorbing layer through an iodine adding device;

[0020] Deionized water is added to the absorption tower through a water adding device. The added deionized water passes through the demisting layer and the packing layer and converges to the bottom of the absorption tower, then flows into the slurry collection tank, passes through the iodine absorption layer and enters the slurry collection tank;

[0021] When the slurry collection tank reaches the high liquid level, the slurry circulation pump is started to establish slurry circulation. During this process, a small amount of iodine in the iodine absorption layer is dissolved;

[0022] When the slurry circulation pump operates normally and the liquid level in the slurry collection tank is normal, stop injecting water into the absorption tower;

[0023] Flue gas containing sulfur dioxide is introduced into the absorption tower through the flue gas inlet, and the flue gas passes through the packing layer and the demisting layer and enters the flue gas discharge device;

[0024] The sulfur dioxide in the flue gas dissolves into water after contacting with the mist slurry. The water that absorbs the sulfur dioxide reacts chemically with iodine after passing through the iodine absorption layer to generate sulfuric acid and hydroiodic acid.

[0025] As the amount of hydroiodic acid in the slurry increases, the amount of iodine dissolved increases, and the slurry's ability to absorb sulfur dioxide increases. Most of the sulfur dioxide in the flue gas is absorbed. The flue gas volume and the circulation volume of the slurry circulation pump are adjusted, and the sulfur dioxide detected by the flue gas exhaust device gradually decreases until it meets environmental protection requirements.

[0026] The iodine-adding device is used to timely replenish iodine to the iodine absorption layer;

[0027] As the circulation absorption proceeds, the density of the slurry in the slurry collection tank becomes higher and higher. When the slurry density reaches above the set value, the flue gas is stopped and the slurry circulation pump is stopped;

[0028] The slurry in the absorption tower is gathered into the slurry collection tank and allowed to stand until the slurry is clearly separated into layers, with the upper layer being the sulfuric acid solution layer and the lower layer being the hydroiodic acid and iodine mixed solution layer;

[0029] Discharge the hydroiodic acid and iodine mixed solution at the bottom of the slurry collection tank into the hydrogen iodide solution collection tank;

[0030] The part of the hydroiodic acid and iodine mixed solution in contact with the sulfuric acid layer in the middle of the slurry collection tank is discharged into the mixed solution collection tank;

[0031] Discharge the sulfuric acid solution at the top of the slurry collection tank into the sulfuric acid collection tank;

[0032] The mixed solution in the mixed liquid collection tank is added to the slurry collection tank through the iodine adding device, and water is added to the slurry collection tank to the normal water level through the water adding device to start the next absorption.

[0033] A further improvement of the present invention is that the set value of the slurry density is 2.5 kg / L.

[0034] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0035] The invention provides a device for absorbing sulfur dioxide in boiler flue gas by using iodine, comprising a flue gas inlet, an absorption tower, a packing layer and a demisting layer; flue gas containing sulfur dioxide can be introduced into the absorption tower through the flue gas inlet, and the flue gas is discharged after passing through the packing layer and the demisting layer in sequence.

[0036] Furthermore, a flue gas booster fan is installed in the flue gas inlet of the present invention, and the flue gas pressure can be increased by the booster fan, thereby overcoming the resistance of the packing layer and the demisting layer.

[0037] The present invention provides a device for absorbing sulfur dioxide in boiler flue gas by utilizing iodine, which also includes a water adding device and a flue gas exhaust device. Desalted water can be added to an absorption tower through the water adding device. The added desalted water passes through a demisting layer and a packing layer and converges to the bottom of the absorption tower. The flue gas passes through the packing layer and the demisting layer and enters the flue gas exhaust device. The flue gas exhaust device can detect the sulfur dioxide content in the exhausted flue gas.

[0038] The present invention provides a device for absorbing sulfur dioxide from boiler flue gas by using iodine, which also includes a slurry collecting tank, an iodine absorbing layer, a slurry circulating pump and an iodine adding device. After the added desalted water passes through a demisting layer and a packing layer and converges to the bottom of an absorption tower, it flows into the slurry collecting tank, passes through the iodine absorbing layer and enters the slurry collecting tank, and volatile iodine is placed in the slurry collecting tank, thereby avoiding direct contact between iodine and hot flue gas, reducing iodine volatilization, and reducing iodine escape; the slurry circulating pump can realize the circulation of the slurry, and the slurry passes through the iodine layer formed by iodine particles during circulation, thereby reducing the amount of iodine used while ensuring the absorption effect. The iodine adding device can timely add granular iodine to the iodine absorbing layer.

[0039] Furthermore, the diameter of the slurry collection tank of the present invention is smaller than that of the absorption tower, and the slurry required to ensure the liquid level of the slurry circulation pump is much smaller than that of the conventional absorption tower, so the consumption of iodine can be greatly reduced.

[0040] Furthermore, the present invention configures a plurality of slurry collecting tanks for one absorption tower, and can realize continuous absorption and static stratification of sulfur dioxide by switching the slurry collecting tanks.

[0041] The present invention provides a device for absorbing sulfur dioxide in boiler flue gas by utilizing iodine, which also comprises a hydrogen iodide solution collecting tank, a mixed liquid collecting tank and a sulfuric acid collecting tank. The hydrogen iodide solution is used to collect hydroiodic acid and iodine mixed liquid at the bottom of the slurry collecting tank, the mixed liquid collecting tank is used to collect the hydroiodic acid and iodine mixed liquid in contact with the sulfuric acid layer in the middle of the slurry collecting tank, and the sulfuric acid solution at the top of the slurry collecting tank is collected by the sulfuric acid collecting tank.

[0042] The present invention provides a method for absorbing sulfur dioxide in boiler flue gas by using iodine. The flue gas inlet introduces flue gas containing sulfur dioxide into the absorption tower, and the flue gas passes through a packing layer and a demisting layer in sequence before being discharged. A water adding device can add desalted water to the absorption tower, and the added desalted water passes through the demisting layer and the packing layer and converges to the bottom of the absorption tower. The flue gas passes through the packing layer and the demisting layer and enters the flue gas discharge device, and the flue gas discharge device detects the sulfur dioxide content in the discharged flue gas in real time. The volatile iodine is placed in a slurry collection tank to avoid direct contact between iodine and hot flue gas, reduce the volatilization of iodine, and reduce the escape of iodine; the slurry circulation pump can realize the circulation of the slurry, and the slurry passes through the iodine layer formed by iodine particles during circulation, thereby reducing the amount of iodine used while ensuring the absorption effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention is a structural block diagram of a device for absorbing sulfur dioxide in boiler flue gas using iodine.

[0044] Description of reference numerals:

[0045] 1. Flue gas inlet, 2. Absorption tower, 3. Packing layer, 4. Demisting layer, 5. Water adding device, 6. Flue gas exhaust device, 7. Slurry collecting tank, 8. Iodine absorption layer, 9. Slurry circulation pump, 10. Iodine adding device, 11. Hydrogen iodide solution collecting tank, 12. Mixed liquid collecting tank, 13. Sulfuric acid collecting tank. DETAILED DESCRIPTION

[0046] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0048] Example 1

[0049] like Figure 1As shown, the present invention provides a device for absorbing sulfur dioxide in boiler flue gas by using iodine, comprising a flue gas inlet 1, an absorption tower 2, a packing layer 3 and a demisting layer 4; the outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2, the packing layer 3 and the demisting layer 4 are sequentially installed in the upper part of the absorption tower 2 from bottom to top, the absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demisting layer 4 can resist the corrosion of sulfuric acid and hydroiodic acid.

[0050] In this embodiment, a flue gas booster fan is installed in the flue gas inlet 1, and the flue gas pressure can be increased by the booster fan to overcome the resistance of the packing layer 3 and the demisting layer 4. The flue gas containing sulfur dioxide is introduced into the absorption tower 2 through the flue gas inlet 1, and then passes through the packing layer 3 and the demisting layer 4 in sequence before being discharged.

[0051] Example 2

[0052] like Figure 1 As shown, the present invention provides a device for absorbing sulfur dioxide in boiler flue gas by using iodine, comprising a flue gas inlet 1, an absorption tower 2, a packing layer 3, a demisting layer 4, a water adding device 5 and a flue gas exhaust device 6; the outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2, the packing layer 3 and the demisting layer 4 are sequentially installed in the upper part of the absorption tower 2 from bottom to top, the absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demisting layer 4 can resist corrosion of sulfuric acid and hydroiodic acid; the water adding device 5 is connected to the upper part of the demisting layer 4 through an atomizing nozzle, the flue gas exhaust device 6 is installed on the top of the absorption tower 2, and the flue gas exhaust device 6 can detect sulfur dioxide and iodine content.

[0053] Example 3

[0054] like Figure 1As shown, the present invention provides a device for absorbing sulfur dioxide in boiler flue gas by using iodine, comprising a flue gas inlet 1, an absorption tower 2, a packing layer 3, a demisting layer 4, a water adding device 5, a flue gas discharge device 6, a slurry collecting tank 7, an iodine absorbing layer 8, a slurry circulating pump 9 and an iodine adding device 10; the outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2, the packing layer 3 and the demisting layer 4 are sequentially installed in the upper part of the absorption tower 2 from bottom to top, the absorption tower 2 can detect sulfur dioxide, the packing layer 3 and the demisting layer 4 can resist the corrosion of sulfuric acid and hydroiodic acid; the water adding device 5 is connected to the flue gas discharge device 6, a slurry collecting tank 7, an iodine absorbing layer 8, a slurry circulating pump 9 and an iodine adding device 10; the outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2, the packing layer 3 and the demisting layer 4 are sequentially installed in the upper part of the absorption tower 2 from bottom to top, the absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demisting layer 4 can resist the corrosion of sulfuric acid and hydroiodic acid; the water adding device 5 is connected to the flue gas discharge device 6 by an atomizing nozzle The smoke exhaust device 6 is connected to the top of the demisting layer 4, and is installed on the top of the absorption tower 2. The smoke exhaust device 6 can detect the sulfur dioxide and iodine content; the top of the slurry collection tank 7 is connected to the bottom of the absorption tower 2, and the iodine absorption layer 8 is a fine-mesh mesh, which is installed on the top of the slurry collection tank 7, and granular iodine is placed on it. The outlet of the iodine adding device 10 is connected to the inlet of the iodine absorption layer 8 to provide granular iodine for the iodine absorption layer 8. The inlet of the slurry circulation pump 9 is connected to the first outlet of the slurry collection tank 7, and the outlet of the slurry circulation pump 9 is connected between the packing layer 3 and the demisting layer 4 through an atomizing nozzle. The slurry collection tank 7 collects volatile iodine, avoids direct contact between iodine and hot flue gas, reduces the volatilization of iodine, and reduces the escape of iodine; the slurry circulation pump 9 can make the slurry pass through the iodine layer formed by iodine particles when circulating, and reduce the amount of iodine used under the premise of ensuring the absorption effect.

[0055] In this embodiment, the first outlet of the slurry collecting tank 7 is arranged at its lower part and close to the bottom, and the diameter of the slurry collecting tank 7 is smaller than that of the absorption tower 2. It is made of a slender, transparent material that can resist corrosion by sulfuric acid and hydroiodic acid. The slurry that can be stored inside it matches the flow rate of the slurry circulation pump 9, which can meet the normal operation of the slurry circulation pump 9.

[0056] In this embodiment, one absorption tower 2 may be equipped with a plurality of slurry collecting tanks 7. By switching different slurry collecting tanks 7, the absorption and static stratification of sulfur dioxide may be continuously performed.

[0057] Example 4

[0058] like Figure 1As shown, the present invention provides a device for absorbing sulfur dioxide in boiler flue gas by using iodine, comprising a flue gas inlet 1, an absorption tower 2, a packing layer 3, a demisting layer 4, a water adding device 5, a flue gas exhaust device 6, a slurry collecting tank 7, an iodine absorbing layer 8, a slurry circulating pump 9, an iodine adding device 10, a hydrogen iodide solution collecting tank 11, a mixed liquid collecting tank 12 and a sulfuric acid collecting tank 13; the outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2, the packing layer 3 and the demisting layer 4 are sequentially installed in the upper part of the absorption tower 2 from bottom to top, the absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demisting layer 4 can resist the corrosion of sulfuric acid and hydroiodic acid; the water adding device 5 is connected to the upper part of the demisting layer 4 through an atomizing nozzle, and the flue gas exhaust device 6 is installed in the absorption tower 2 The top of the slurry collecting tank 7 is connected to the bottom of the absorption tower 2, the iodine absorbing layer 8 is a fine mesh, installed on the upper part of the slurry collecting tank 7, and granular iodine is placed thereon. The outlet of the iodine adding device 10 is connected to the inlet of the iodine absorbing layer 8 to provide granular iodine for the iodine absorbing layer 8. The inlet of the slurry circulating pump 9 is connected to the first outlet of the slurry collecting tank 7, and the outlet of the slurry circulating pump 9 is connected between the packing layer 3 and the demisting layer 4 through an atomizing nozzle; the second outlet of the slurry collecting tank 7 is at its bottom and is divided into three strands, the first strand is connected to the inlet of the hydrogen iodide solution collecting tank 11, the second strand is connected to the inlet of the mixed liquid collecting tank 12, and the third strand is connected to the inlet of the sulfuric acid collecting tank 13. The hydrogen iodide solution collecting tank 11 is used to collect the hydroiodic acid and iodine mixed solution at the bottom of the slurry collecting tank 7, the mixed solution collecting tank 12 is used to collect the hydroiodic acid and iodine mixed solution in contact with the sulfuric acid layer in the middle of the slurry collecting tank 7, and the sulfuric acid collecting tank 13 is used to collect the sulfuric acid solution at the top of the liquid collecting tank 7.

[0059] Example 5

[0060] The present invention provides a method for absorbing sulfur dioxide from boiler flue gas by using iodine. The method is based on a system for absorbing sulfur dioxide from boiler flue gas by using iodine. Figure 1As shown, the system includes a flue gas inlet 1, an absorption tower 2, a packing layer 3, a demisting layer 4, a water adding device 5, a flue gas exhaust device 6, a slurry collecting tank 7, an iodine absorbing layer 8, a slurry circulating pump 9, an iodine adding device 10, a hydrogen iodide solution collecting tank 11, a mixed liquid collecting tank 12 and a sulfuric acid collecting tank 13; the outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2, the packing layer 3 and the demisting layer 4 are sequentially installed in the upper part of the absorption tower 2 from bottom to top, the absorption tower 2 can detect sulfur dioxide, the packing layer 3 and the demisting layer 4 can resist the corrosion of sulfuric acid and hydroiodic acid; the water adding device 5 is connected to the upper part of the demisting layer 4 through an atomizing nozzle, the flue gas exhaust device 6 is installed on the top of the absorption tower 2, and the flue gas exhaust device 6 The invention can detect the content of sulfur dioxide and iodine; the top of the slurry collecting tank 7 is connected to the bottom of the absorption tower 2; the iodine absorbing layer 8 is a fine-mesh mesh and is installed on the upper part of the slurry collecting tank 7, on which granular iodine is placed; the outlet of the iodine adding device 10 is connected to the inlet of the iodine absorbing layer 8 to provide granular iodine for the iodine absorbing layer 8; the inlet of the slurry circulating pump 9 is connected to the first outlet of the slurry collecting tank 7; the outlet of the slurry circulating pump 9 is connected between the packing layer 3 and the demisting layer 4 through an atomizing nozzle; the second outlet of the slurry collecting tank 7 is at its bottom and is divided into three branches, the first branch is connected to the inlet of the hydrogen iodide solution collecting tank 11, the second branch is connected to the inlet of the mixed liquid collecting tank 12, and the third branch is connected to the inlet of the sulfuric acid collecting tank 13.

[0061] The method includes:

[0062] Adding granular iodine to the iodine absorbing layer 8 through the iodine adding device 10;

[0063] Deionized water is added to the absorption tower 2 through the water adding device 5. The added deionized water passes through the demisting layer 4 and the packing layer 3 and converges to the bottom of the absorption tower 2, then flows into the slurry collecting tank 7, passes through the iodine absorbing layer 8 and enters the slurry collecting tank 7;

[0064] When the slurry collecting tank 7 reaches the high liquid level, the slurry circulation pump 9 is started to establish slurry circulation, during which a small amount of iodine in the iodine absorption layer 8 is dissolved;

[0065] When the slurry circulation pump operates normally and the liquid level in the slurry collection tank 7 is normal, stop injecting water into the absorption tower 2;

[0066] Flue gas containing sulfur dioxide is introduced into the absorption tower 2 through the flue gas inlet 1, and the flue gas passes through the packing layer 3 and the demisting layer 4 and enters the flue gas exhaust device 6;

[0067] The sulfur dioxide in the flue gas dissolves into water after contacting with the mist slurry. The water that absorbs the sulfur dioxide reacts chemically with iodine after passing through the iodine absorption layer 8 to generate sulfuric acid and hydroiodic acid.

[0068] As the amount of hydroiodic acid in the slurry increases, the amount of iodine dissolved increases, the slurry's ability to absorb sulfur dioxide increases, and most of the sulfur dioxide in the flue gas is absorbed. The flue gas volume and the circulation volume of the slurry circulation pump are adjusted, and the sulfur dioxide detected by the flue gas exhaust device 6 gradually decreases until the environmental protection requirements are met;

[0069] The iodine-adding device 10 is used to timely replenish iodine to the iodine absorption layer 8;

[0070] As the cyclic absorption proceeds, the density of the slurry in the slurry collection tank 7 becomes higher and higher. When the slurry density reaches above 2.5 kg / L, the flue gas is stopped and the slurry circulation pump 9 is stopped.

[0071] The slurry in the absorption tower 2 is gathered into the slurry collection tank 7 and allowed to stand until the slurry is clearly separated into layers, with the upper layer being the sulfuric acid solution layer and the lower layer being the hydroiodic acid and iodine mixed solution layer;

[0072] Discharge the hydroiodic acid and iodine mixed solution at the bottom of the slurry collection tank 7 to the hydrogen iodide solution collection tank 11;

[0073] The part of the hydroiodic acid and iodine mixed solution in contact with the sulfuric acid layer in the middle of the slurry collection tank 7 is discharged into the mixed solution collection tank 12;

[0074] Discharge the sulfuric acid solution in the upper part of the slurry collection tank 7 to the sulfuric acid collection tank 13;

[0075] The mixed solution in the mixed solution collection tank 12 is added to the slurry collection tank 7 through the iodine adding device, and water is added to the slurry collection tank 7 through the water adding device 5 until the normal water level of the slurry collection tank 7 is started for the next absorption.

[0076] Embodiment 6:

[0077] like Figure 1 As shown, in this embodiment, an absorption tower 2 with a diameter of 2 meters is used. In order to maintain the normal operation of the slurry circulation pump, the liquid level must be maintained at 1 meter, so the required slurry volume is about 3m 3 , absorption and static separation cannot be achieved simultaneously, and continuous production is not possible.

[0078] In the method of the present invention, the diameter of the absorption tower 2 is 2 meters, two slurry absorption tanks 7 are used, each with a diameter of 0.5 meters, the slurry level is 1 meter, and the amount of slurry required for a single slurry absorption tank is approximately 0.2m 3 The usage of iodine in a single absorption tank is 7% of the conventional usage, but it does not affect the normal operation of the slurry circulation pump 9. Two slurry absorption tanks 7 are set up, one for absorption and the other for static separation, to achieve continuous production.

[0079] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A device for absorbing sulfur dioxide from boiler flue gas using iodine, characterized in that: It comprises a flue gas inlet (1), an absorption tower (2), a packing layer (3), a demisting layer (4), a water adding device (5), a flue gas exhaust device (6), a slurry collecting tank (7), an iodine absorbing layer (8), a slurry circulation pump (9) and an iodine adding device (10); The outlet of the flue gas inlet (1) is connected to the inlet of the absorption tower (2), the packing layer (3) and the demisting layer (4) are sequentially installed in the upper part of the absorption tower (2) from bottom to top, the absorption tower (2) can detect sulfur dioxide, and the packing layer (3) and the demisting layer (4) can resist corrosion by sulfuric acid and hydroiodic acid; The water adding device (5) is connected to the upper part of the demisting layer (4) through an atomizing nozzle, and the smoke exhaust device (6) is installed on the top of the absorption tower (2). The smoke exhaust device (6) can detect the content of sulfur dioxide and iodine; The top of the slurry collecting tank (7) is connected to the bottom of the absorption tower (2); the iodine absorbing layer (8) is a fine-mesh mesh installed on the upper part of the slurry collecting tank (7); granular iodine is placed on the iodine absorbing layer; the outlet of the iodine adding device (10) is connected to the inlet of the iodine absorbing layer (8) to provide granular iodine for the iodine absorbing layer (8); the inlet of the slurry circulating pump (9) is connected to the first outlet of the slurry collecting tank (7); and the outlet of the slurry circulating pump (9) is connected between the packing layer (3) and the demisting layer (4) through an atomizing nozzle.

2. The device for absorbing sulfur dioxide from boiler flue gas by using iodine according to claim 1, characterized in that: A flue gas booster fan is installed in the flue gas inlet (1), and the booster fan is used to increase the flue gas pressure to overcome the resistance of the filler layer (3) and the demisting layer (4).

3. The device for absorbing sulfur dioxide from boiler flue gas by using iodine according to claim 1, characterized in that: The first outlet of the slurry collection tank (7) is arranged at its lower part and close to the bottom.

4. The device for absorbing sulfur dioxide from boiler flue gas by using iodine according to claim 1, characterized in that: The diameter of the slurry collection tank (7) is smaller than that of the absorption tower (2), and the slurry that can be stored therein matches the flow rate of the slurry circulation pump (9), which can meet the normal operation of the slurry circulation pump (9).

5. The device for absorbing sulfur dioxide from boiler flue gas by using iodine according to claim 1, characterized in that: An absorption tower (2) is equipped with a plurality of slurry collecting tanks (7), and the absorption and static stratification of sulfur dioxide can be continuously performed by switching the slurry collecting tanks (7).

6. The device for absorbing sulfur dioxide from boiler flue gas by using iodine according to claim 1, characterized in that: It also includes a hydrogen iodide solution collecting tank (11), a mixed liquid collecting tank (12) and a sulfuric acid collecting tank (13). The second outlet of the slurry collecting tank (7) is at the bottom thereof and is divided into three branches, the first branch is connected to the inlet of the hydrogen iodide solution collecting tank (11), the second branch is connected to the inlet of the mixed liquid collecting tank (12), and the third branch is connected to the inlet of the sulfuric acid collecting tank (13).

7. A method for absorbing sulfur dioxide from boiler flue gas using iodine, characterized in that: The method is based on a device for absorbing sulfur dioxide from boiler flue gas using iodine as described in claim 6, comprising: Adding granular iodine to the iodine absorbing layer (8) through an iodine adding device (10); Deionized water is added to the absorption tower (2) through a water adding device (5); the added deionized water passes through a demisting layer (4) and a packing layer (3) and converges to the bottom of the absorption tower (2), then flows into a slurry collecting tank (7), passes through an iodine absorbing layer (8), and enters the slurry collecting tank (7); When the slurry collecting tank (7) reaches a high liquid level, the slurry circulation pump (9) is started to establish slurry circulation, during which a small amount of iodine in the iodine absorption layer (8) is dissolved; When the slurry circulation pump operates normally and the liquid level in the slurry collection tank (7) is normal, the injection of water into the absorption tower (2) is stopped; Flue gas containing sulfur dioxide is introduced into the absorption tower (2) through the flue gas inlet (1), and the flue gas passes through the packing layer (3) and the demisting layer (4) and enters the flue gas discharge device (6); The sulfur dioxide in the flue gas dissolves into water after contacting the mist slurry, and the water that absorbs the sulfur dioxide passes through the iodine absorption layer (8) and then reacts chemically with iodine to generate sulfuric acid and hydroiodic acid; As the amount of hydroiodic acid in the slurry increases, the amount of iodine dissolved increases, the slurry's ability to absorb sulfur dioxide increases, and most of the sulfur dioxide in the flue gas is absorbed. The flue gas volume and the circulation volume of the slurry circulation pump are adjusted, and the sulfur dioxide detected by the flue gas exhaust device (6) gradually decreases until the environmental protection requirements are met; timely replenishing iodine to the iodine absorbing layer (8) through the iodine adding device (10); As the cyclic absorption proceeds, the density of the slurry in the slurry collection tank (7) becomes higher and higher. When the slurry density reaches a set value or higher, the flue gas is stopped and the slurry circulation pump (9) is stopped. The slurry in the absorption tower (2) is collected in the slurry collection tank (7) and allowed to stand until the slurry is clearly separated into layers, with the upper layer being a sulfuric acid solution layer and the lower layer being a mixed solution layer of hydroiodic acid and iodine; Discharge the hydroiodic acid and iodine mixed solution at the bottom of the slurry collection tank (7) into the hydrogen iodide solution collection tank (11); Discharge the portion of the hydroiodic acid and iodine mixed solution in contact with the sulfuric acid layer in the middle of the slurry collection tank (7) into the mixed solution collection tank (12); Discharge the sulfuric acid solution in the upper part of the slurry collection tank (7) into the sulfuric acid collection tank (13); The mixed solution in the mixed solution collection tank (12) is added to the slurry collection tank (7) through the iodine adding device, and water is added to the slurry collection tank (7) to the normal water level through the water adding device (5) to start the next absorption.

8. The method of absorbing sulfur dioxide from boiler flue gas by using iodine according to claim 7, characterized in that: The set value of slurry density is 2.5 kg / L.

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